add getServiceCredsByLabel

getServiceCredsByLabel is like getServiceCreds except that the label is used.
* internal function getServiceByLabel added
* docs update
* tests update

Note, other get*ByLabel functions may be desired. This is just a starting point.

See discussion #3

README.md

@@ -106,6 +106,7 @@ The returned object also has the following methods available:
 * `appEnv.getService(spec)`
 * `appEnv.getServiceURL(spec, replacements)`
 * `appEnv.getServiceCreds(spec)`
+* `appEnv.getServiceCredsByLabel(spec)`
 
 If no value can be determined for `port`, and the `name` property on the
 `options` parameter is not set and cannot be determined,
@@ -285,7 +286,20 @@ If there is a service that matches the `spec` parameter, the value of it's
 `credentials` property on the service, an empty object - `{}` - will be
 returned.
 
+**`appEnv.getServiceCredsByLabel(spec)`**
+--------------------------------------------------------------------------------
+
+Returns the `credentials` object of a service by label.
+
+The `spec` parameter is similar to that used by the
+`appEnv.getServiceURL()` method except matching by label instead of by name.
+If there is no service whose label matches the `spec` parameter,
+this method will return `null`.
 
+If there is a service whose label matches the `spec` parameter, the value of
+it's `credentials` property will be returned.  If for some reason, there is no
+`credentials` property on the service, an empty object - `{}` - will be
+returned.
 
 testing with Cloud Foundry
 ================================================================================

lib-src/cfenv.coffee

@@ -69,6 +69,23 @@ class AppEnv
 
     # no matches
     return null
+  #-----------------------------------------------------------------------------
+  getServiceByLabel: (spec) ->
+
+    # set our matching function
+    if _.isRegExp spec
+      matches = (label) -> label.match spec
+    else
+      spec = "#{spec}"
+      matches = (label) -> label is spec
+
+    services = @getServices()
+    for label, service of services
+      if matches label
+        return service
+
+    # no matches
+    return null
 
   #-----------------------------------------------------------------------------
   getServiceURL: (spec, replacements={}) ->
@@ -106,6 +123,12 @@ class AppEnv
     service     = @getService spec
     return null unless service?
 
+    return service.credentials || {}
+  #-----------------------------------------------------------------------------
+  getServiceCredsByLabel: (spec) ->
+    service     = @getServiceByLabel spec
+    return null unless service?
+
     return service.credentials || {}
 
 #-------------------------------------------------------------------------------

tests/test-core.coffee

@@ -241,6 +241,37 @@ describe "appEnv", ->
     creds  = appEnv.getServiceCreds "service-a"
     creds  = JSON.stringify(creds)
     expect(creds).to.be '{"url":"foo"}'
+  #-----------------------------------------------------------------------------
+  it "local - getServiceCredsByLabel()", ->
+
+    #-------------------------------------------
+    vcap = getVCAPServicesWithCreds "service-a",
+      url: "foo"
+
+    appEnv = cfenv.getAppEnv {vcap}
+    creds  = appEnv.getServiceCredsByLabel "service-b"
+    expect(creds).to.be null
+    #-------------------------------------------
+    vcap = getVCAPServicesWithCreds "service-a",
+      url: "foo"
+
+    appEnv = cfenv.getAppEnv {vcap}
+    creds  = appEnv.getServiceCredsByLabel "service-a"
+    expect(creds).to.eql {url:"foo"}
+    #-------------------------------------------
+    vcap = getVCAPServicesWithCreds "service-a",
+      url: "foo"
+
+    appEnv = cfenv.getAppEnv {vcap}
+    creds  = appEnv.getServiceCredsByLabel /service.*/
+    expect(creds).to.eql {url:"foo"}
+    #-------------------------------------------
+    vcap = getVCAPServicesWithCreds "service-a",
+      url: "foo"
+
+    appEnv = cfenv.getAppEnv {vcap}
+    creds  = appEnv.getServiceCredsByLabel /disservice.*/
+    expect(creds).to.be null
 
   #-----------------------------------------------------------------------------
   it "remote - VCAP_APPLICATION", ->